Method and apparatus for utilizing exhaust steam



May 28, 1957 F. w. RIEHL' 2,793,502

msmon AND APPARATUS FOR UTILIZING smusr STEAM Filed Nov. 19. 1943 2 Shets-Sheet 1 I2 67 as 65 7 9 f f r I 76 /07 F r e. 3

24 Z2 2o fl3 l5 2/ 29 o O 0 I6. 2/8 [9 Q33 32 INVENTOR.

Frederick W. Riehl ATTORNEY May 28, 1957 F. w. RIEHL 2,793,502

METHOD AND APPARATUS FOR UTILIZING EXHAUST STEAM Filed Nov. 19. 1948 2 Sheets-Sheet 2 L 87 F IG. 6

INVENTOR. 5 Frederick W. Rieh BY %{d- 7 ATTORNEY heat cycle and apparatus;

United States Patent METHOD AND APPARATUS FOR UTILIZING EXHAUST STEAM My invention, which is a continuation in part of my application Serial No. 530,131, now abandoned, is directed to improvements in heat cycles and apparatusfor use therein, and has as a general object the provision, of a heat cycle particularly adapted for use with steamdriven prime movers and the like, which increases the amount of useful work capable of performance by the addition of 'a given quantity of heat to the cycle.

Other important objects of my invention include the provision of a heat cycle of the type described, which in addition to operating in a more efficient manner also provides an adequate supply of distilled makeup water for the boilers, which also aids materially in cooling the main condenser, and which makes available substantial quantities of low temperature steam for process'use when and if required.

Additional objects include the provision of a novel and efiicient apparatus for carrying out various steps of my procedure including means for automatically regulating the quantity of water circulated through the cycle and which occupies considerably less space than conventional apparatus employed in such heat or steam cycles.

Various additional objects pertaining to both my heat cycle and the apparatus for use therein will be apparent from the following detailed description and from the appended drawings in which: g

Fig. l is a diagrammatic elevation of a steamdriven turbo-generator installation incorporating a simplified;

form of my invention;

Fig. 2 is a diagrammatic elevation ofa steam-driven turbo-generator incorporating a modified form of my invention; V t g Fig. 3 is a diagrammatic view of a steam-driventurbogenerator installation incorporating my invention;

Fig. 4 is a diagrammatic elevation of a steam-driven turbo'generator illustrating a further modificationof my Fig. 5 is a diagrammatic vertical section of a vacuum evaporator for use in my cycle; and

Fig. 6 is a diagrammatic verticalsection of an alternative vacuum evaporator.

' Since steam is the most commonly utilized vapor medium for the transformation of heat energy into mechanical energy, I shall confine my disclosure primarily to steam cycles, it being understood that liquids other than water may be substituted if required by special conditions. Furthermore, since my cycle is particularly well adapted for use withturbines, my disclosure will be further confined to the application of my invention to the regenerative heat cycle of a steam-driven multistage turbo-generator. It will be obvious to those skilled in the art that the invention hereindisclosed may be applied to other similar steam cycles, such as those employing reciprocating engines without material altera-' tion.

Although large capacity turbo-generator installations are generally considered as being highly eificient, it has 2mm Patented May 28 1957 ICQ 2 been known "for many years that more than fifty percent of the heat generated for driving the turbine is wasted and dissipated without performing any useful work. Since the efiiciency of such. an installation is the ratio between the useful work performed and the quantity of work which could be theoretically performed by the amount of heat added to the system, a saving of heat results in an increase in efficiency.

The principal loss of heat in'these and similar installa tions occurs in the main condenser where the latent heat of evaporation carried by the steam exhausted intothe main condenser from theturbine is extracted by heat exchange with Water flowing through condenser tubes, thus condensing .the steam and heating the cooling water. It has also been recognized that the continuous maintenance of a very. low subatmospheric pressure in the condenser is essential to the efiicient operationof such installations, with the result that modern condensers are. designed to use substantial quantities of cooling water which is heated only a relatively few degrees during its passage through the condenser. As a result, the temperature of the cooling water discharged from the tubes of the condenser is only slightly above that of the cold water entering the condenser and the utilization of this heat energy in the water has therefore been considered impractical for use in the past.

To clearly understand the method and apparatus I employ for utilizing at least a portion of the heat contained in the exhaust steam, it. must be remembered that vapor contains a quantity of heat known as the latent heat of vaporization, this being the amount of heat which must be added to convert water at boiling temperature to vapor at the same temperature, and that this heat is released only when the vapor is condensed.

to a liquid. It must also be remembered that vapor or steam exists at substantiallyany temperature, provided the necessary pressure is maintained. Stated in other words, water may be evaporated at say 80 F. if the pressure against the water is sufficiently low and in so effecting a translation of the waste heat of exhaust steam into heat capable ofperforming useful work. In brief, I pass steam through an exhauster or evacuator passage, hereinafter referred to as a steam jet, in such manner as to induct with it low temperature vapor existing at a subatmospheric pressure. This increases the pressure of the vapor by compression and heats the low temperature vapor without causing condensation, and results in the formation of a composite vapor containing a total quantity of heat substantially greater than the total quantity of heat in the steam employed to operate the jet. Furthermore,

this vapor is at a temperature and pressure sufficiently high to permit its utilization in conventional heat exchange apparatus. The vapor which is inducted through the jet may be exhauststeam drawn directly from a condenser, or it may be a vapor formed under sub-atmospheric pressure by heat exchange with the exhaust steam, as for example through the medium of the condenser cooling water. i

As a result of this process, the main condenser cooling system is not called upon to extract all of the heat in the exhaust steam and thus permits the maintenance of a lower atmospheric pressure in the condenser. Furthermore, this quantity of, heat is translated into a usable form and may be efliciently employed, for example, in heating makeup water. and/or condensate, or in the operation of Such a vapor, however,

various items of equipment such as space heaters or vacuum evaporators requiring low temperature steam for operation. The size of the cooling tower, spray pond or the. like, used to cool condenser cooling water, may also be reduced, since it will receive less heat from the condenser for dissipation.

This procedure. is illustrated in simplified form in Fig. 1 wherein I have shown a turbine '10 coupled to a generator 11- and} supplied with high-pressure steam through a pipe 12which communicates with boilers 13. Steam from the turbine exhausts into a condenser 14 maintained at a low sub-atmospheric pressure and having internal tubes 28 through which cooling water may be circulated. A steam jeto r exhauster 16 communicates with the upper portion of the condenser, preferably through a check valve 15, and dis'chargesinto a pipe l8, the jet 16 being operated by steam delivered tothe jet by a pipe 17 having. a valve 20 communicating, for example, with an intermediate stage withtheturbine. 10. The pipe 18 may be connected to a having a branch pipe 19 with a valve 21 through which connection may bernade to processing apparatus requiring. low temperature steam. The other branch of theT ma'y be, led to feed water heater 22, which receives condensate from a hot well 34 on the main condenser 14 througha pump 33 and a pipe 32. From the heater 22 a pipe 23' may deliver heated condensate to the boilers 13, although it is contemplated that considerable apparatus such asa deaerator and addition heaters would be interposed before and after this point in an actual installation.

A branch line 24 having a valve 26 may interconnect the high pressure steam line 12 and the bled steam line 17 to, supply such additional steam as may be required to the jet 16 inorder to yield the desired pressure and temperature in the pipe 18. I prefer to regulate the temperature. and pressure in the pipe 18 automatically, as by providing a solenoid or diaphragm valve 27 actuated by temperature and/or pressure ditferentials in the pipe 17. For. example, if the pressure of steam in the pipe 18 should fall below that required for process use, the valve 27 automatically opens to admit high pressure steam to the jet 1 6, whereas, if the pressure in the steam line 12 falls below a predetermined minimum the valve 27 will be moved towards a closed position, thus making more steam available-for theturbine 10.

If desired, make up water may beadded' directly to the condenser 14' through a spray 29, preferably disposed above the tubes 28,.and a temperature alarm 31 is provided to; warn the operator of any unreasonable increases or decreases in the temperature. and/or. pressure within the condenser.

V Inoperation, a portion of theexhaust steam entering the condenserl 4; will be condensed by contact with the tubes 28;and the makeup waterand will vaporize and deaerate the makeup wateraddedto the condenser through the spray 29. The balance ofthe exhaust steam will be drawn through the jet 16 without condensation and-there in compressed and heated for further use. i The temperatureofthe bled steam will, of course, be reduced in this process, but the volume of vapor in the pipe 18 will be greater than that capable of formation by the bled steam alone. Since condensation has not occurred, the total quantity of heat in the composite vapor in the pipe 18 includcs the latent heat of evaporation originally contained in the exhaust steam, and as a result the total quantity of heat in the vapor in the pipe 18 is substantially greater than the heat content of the bled steam. introduced into the pipe 18 through the pipe 17; Substantially all of this-heat is returned to the primary cycle by employing the vapor frompipelS, to heat condensate inthe feed water heater 22;'or may, as previously described, be used externally of the cycle when desired; It is obviously essential to the proper operation of my process that condensation be avoided in' the jet 16, which may be designed by known principles to accomplish this function.

Fig. 2 diagrammatically illustrates a heat cycle basically similar to that shown in Fig. l, but in which heat exchange is etfected indirectly through the medium of main condenser cooling water. For example, I provide a primary cycle wherein steam from boilers 13 is passed to the turbine 10 through a pipe 12 into a condenser 36, where it is condensed and collected in a hot well 37, thence to condensate pump 78, heater 77, and through pump 83 back to the boilers 13. A condenser 36 in the form shown incorporates a primary and a secondary cooling system, the primary system being conventional in design and comprising banks of tubes 35 within the condenser 36 communicating with inlet and outlet cooling water pipes 38' and 39-respectively. The auxiliary cooling system also includes banks of; tubes 30 disposed within the condenser and communicating with inlet and outlet pipes 41 and 42 respectively, through which water or other suitable liquid cooling medium is circulated by a pump 48. The pump 48 discharges heated cooling water to a header 47 which is connected to a series of tubes 46 disposed within a vacuum evaporator, generally designated 43. The vacuum evaporator comprises ashell 44 surrounding the tubes and supporting a water box 49 communicating with a second pass of tubes 46, which serve to conduct the condenser cooling water to a return header 51, in turn connected to inlet pipe 41 of the secondary condenser cooling system. A pipe 64 communicating with pipe 42 may be employed to supply water to the system when needed and an overboard line 84" having a valve 86- may be utilized to discharge collected solids from the system. Similarly, a drain cock 87 may be mounted in the bottom of the vacuum evaporator 43. Preferably, the tubes 30 of the auxiliary cooling system include three way valves 25-25 communicating with the inlet and outlet pipes 38 and 39 respectively, thus permitting circulation of water through the tubes 30 in a closed circuit independent of the tubes 35 of the primary condenser cooling system, or selectively permittingi introduction of heated cooling water from discharge pipe 391to inlet pipe 42, and the return of cooled water from pipe 41 to inlet pipe 38.

In the upper portion of the vacuum evaporator 43 I provide a steam jet or exhauster 66 operated by steam bled from an intermediate stage of the turbine 10 and connected to the jet 66 through apipe 67 having a check valve 68. The quantity of steam discharged through the jet 66 is suflicient to maintain the vacuum evaporator 43 at an absolute pressure below that maintained in the condenser 36, with the result that water may be evaporated; in the vacuum evaporator at a temperature below the temperature of the exhaust steam in the condenser. If desired, a conduit 63 may interconnect the condenser 36 and the vacuum evaporator 43 to purge the condenser 36 of air and other non-condensible vapors, thus eliminating a steam jet air pump from the cycle. I also provide a check valve 65 for preventing reverse flow through the jet 66.

The water evaporated within the vacuum evaporator 43 is primarilymakeup water supplied thereto through a pipe 52. I prefer to introduce makeup water to the evaporator through a pipe 53 connected to the pipe 52 and to a float valve 54 disposed within the vacuum evaporator 43. The valve 54in turn communicates with a spray pipe 56 disposed within the evaporator 43 above the tubes 46-. The float valve 54 is a low level water control for the entire cycle and-functions to admit water to the system through'the spray 56 when the water level in the evaporator 43 drops below a predetermined point.

There are several operating conditions in which it is not desirable to add substantial quantities of makeup water, although some makeup water is required almost continuously. I therefore provide means for passing water which collects in the bottom of the evaporator upwardly over the tubes 46 in order to vaporize additional quantities of water. This'I accomplish by mounting within the evaporator 43 a, jet 59 communicating with the pipe. 62 through a float controlled valve 62. The jet 59 is disposed in such manner as to impinge i'ts stream upon arotatably mounted wheel 58 within the evaporator 43, and thus rotate the wheel which picks up 'water from the bottom of the evaporator and discharges it to a trough 57 mounted within the evaporator above the tubes 46. The trough 57 is provided with a multiplicity of openings in its bottom and serves to distribute water delivered by the wheel 58 evenly over the tubes 56. The valve 62 serves as a high level control valve and functions to regulate or terminate the flow through the jet 59 in instances Where the level of water within the evaporator has risen beyond that required for operation, it being understood that during such periods the valve 54 has moved to closed position. Details of the evaporator 43 are more clearly shown in Fig. 5.

The bled steam passing through the jet 66 and the low temperature vapor extracted by the jet 66 from the vacu um evaporator 43 is discharged into a pipe 72 having a valve 73 communicating with a diaphragm control 74. A pipe 81 may conduct these vapors to a heater 77 and may also be provided with a branch pipe 80 having a valve 83 for diverting all or any portion of the vapor to process use. If desired, a valve 82 may also be provided for regulating the flow of vapor to the heater 77. Since the amount of heat contained in the steam passing through the pipe 72 may be insufficient in quantity, temperature, or pressure, I also provide a bled steam line 79 heading from an intermediate stage of the turbine to the heater 77.

A branch line 69 may interconnect the high pressure steam line 12 with the pipe 67 through a valve 71 and employed to increase the temperature and pressure of steam in the line 67 when necessary. Preferably I also provide a diaphragm control 76 arranged to actuate a valve 76a coordinated with valve 73 to control the tem perature and pressure of steam in the pipe 67 as required by controls 75 disposed in the pipe 72 on either side of the valve 73. The controls 75 operate the valves 73 and 76a in unison and in such manner as to open both valves if the pressure on the outlet side of the valve 73 should drop below a predetermined minimum. Similarly these valves are moved towards the closed position if the pressure rises beyond a predetermined point. Furthermore, if the load on the turbine 10 should increase so that a greater quantity of heat would necessarily be extracted in the vacuum evaporator 43, the valves 73 and 760 will open to increase the capacity of the jet 66 to extract vapor from the evaporator 43.

In operation, the water circulating in the secondary condenser cooling system through the pipes 41 and 42 is heated by heat exchange with exhaust steam in condenser 36 and this heat is extracted within the vacuum evaporator 43 by the evaporation of makeup water. As the vapor is formed it absorbs large quantities of heat from the water circulating in the pipes 46, thus reducing the temperature of the water and changing the heat from sensible heat into latent heat of vaporization. The vapor formed by evaporation of make up water is extracted by the jet 66, which is preferably surrounded by insulation.

As previously described, the vapor from the evaporator 43 is compressed and heated during its passage through the jet 66, and may be employed to perform useful work, such as in process use or in the heating of condensate. This particular form of apparatus is highly efficient and serves to provide all of the makeup water required by the-boilers 13 in distilled form, thus reducing the formation of scale inthe boilers 13. It should also be noted that the condenser 36 will be more etficiently cooled since the water returned to the condenser through the pipe 41 will be at a uniform low temperature. The vacuum in the condenser will therefore be greater than would otherwise be feasible.

As shown in Fig. 3, my cycle may include a. plurality of yacuum evaporators, this being particularly true Where all or substantially all of the heat extracted. from the exhaust steam is to be returned tothe primary cycle. As previously described in connection with Fig. 2, exhaust steam from turbine 10 is passed to condenser 36 having a primary condenser circulating water system connected to inlet and outlet pipes 38 and 39. A secondary cooling system is also provided for supplying heat vacuum evaporators 89 and 91 from tubes 92 preferably disposed in the upper portion of the condenser 36. An outlet pipe 93 connects the tubes 92 with a pump 94 which discharges into a pipe 96 connected with tubes 97 in evaporator 91 and through a branch line 98 with tubes 99 disposed in evaporator 89. The tubes 97 and 99 discharge to a pipe 101 which returns the cooled Water to the tubes 92 in the condenser 36. Condensate from the condenser 36 is collected in a hot well 37 and discharged through a pump 78 into a pipe 102, communicating with a deaerator 103, which also acts as a feed water heater and condenser for the discharge of the vacuum evaporator 89. The deaerator 103 is constructed to remove air from the condensate in conventional manner.

Condensate collects in a well 104 on the deaerator 103 and is discharged by a pump 106 through a pipe 107 to a medium pressure stage heater 108, which in turn discharges condensate to a high pressure stage heater 109 from which the heated condensate is delivered to the boilers 13 through a pipe 111. Steam for operating the high pressure heater 109 is obtained through a bleed line 112 communicating with one of the high pressure stages of the turbine. heater 109 collects in a trap 113 and passes through a pipe 114 to the heater 108. In addition to the steam passed from the heater 109 to the heater 108, steam is delivered to the latter through a pipe 116, which receives the discharge of a jet 117 in the vacuum evaporator 91, the jet 117 being similar to the jets 16 and 66 previously described, and having a check valve at or near its discharge. Steam for operating the jet 117 is supplied through pipe 118 which leads from a medium pressure stage of the turbine, and the water formed by the condensation of the steam in heater 108 collects in trap 119 and passes to the deaerator 103 through pipe 121. A vent line 122 connects the heater 108 with the deaerator 103 to discharge air collecting in the heater 108. i A jet 123, also similar to jet 66, is'disposed Withi vacuum evaporator 89, and is supplied by pipe 124 with bled steam obtained from a low prcssurestage of the turbine, the discharge of the jet 123 being delivered by pipe 126 through a check valve to the deaerator 103. The vapors thus delivered are condensed in the deaerator and added to the condensate along with water flowing to the deaerator through the line 121. Makeup water may be added to the system through a pipe 127 having a control valve 128 and a check valve 129 communicating with branch pipes 131 and 132 leading to the evaporators 91 and 89 respectively, these lines being connected in a manner previously described in connection with evaporator 43 in Fig. 2. In addition, however, condensate from pipe 102 may be added to the vacuum evaporator 89 and 91 through a branch line 133 com municating with the pipes 131 and 132 and with the pipe 102 through a check valve 134 and a control valve 136.

the vacuum evaporators and only in some instances is it necessary to add condensate through the pipe 133..

The temperature and pressure of the bled steam necessary to operate my steam jets is dependent upon the.

The condensed. steam from thework to'be done by the jet, as for example the amount of water to be; evaporated in the evaporator, and upon thepressure conditions on the discharge side of the jet. By way of illustration, if only a relatively small amount of water is to be evaporated in the first evaporator 89, and the-deaerator 103 is. of the low pressure type, the steam bled to jet 123 may beof sub-atmospheric pressure, assuming of course that the absolute pressure of the steam isgreater than the absolute pressure in the deaerator 103, thus creating the necessary pressure diiferential.

A slightly different system utilizinga single evaporator, but'otherwise basically similar to the system illustrated in Fig; 2 is illustrated in Fig. 4, wherein a multi-stage turblue-.10 is supplied with steam from boilers 13 through a high pressure line 12 and exhausts into a condenser 36 having a primary cooling system connected to pipes 38 and 39, a secondary cooling system 92 disposed within thev condenser 36. The tubes 92 are connected to an inlet line 137 and an outlet line 138, the latter also connecting through a check valve 139 to a pipe 141, which receives condensate discharged by pump 78 from hot well 37" of condenser 36. Pipe 138 also communicates with a pump 142 driven by a'motor 143 which circulates water from line138 through tubes 46' discharging into pipe 137. The tubes 46 are disposed in a vacuum evaporator 144 which is in many respects similar to the evaporator 43 previously described. The evaporator 144, which is interchangeable with the evaporator 43 includes a shell 44 within which the tubes 46', a pivoted wheel 58, a jet 59', a spray 56, and a float control valve 54 are mounted. Each of these units performs a function similar to that described in connection with the evaporator 43 and are similarly arranged.

In this modification, however, I provide a pump 145 which forces water from the bottom of the evaporator 144 through a pipe 147 past a control valve 148 to the spray 56,thus providing positive means for recirculating water within the evaporator 144 without the addition of makeup water. A check valve 149 may interconnect pipes 147 and 141 to introduce condensate into the evaporator 144. Makeup water is supplied to jet 59 through a pipe 151 and valve 178, which also communicates with pipe 147 through a check-valve 152 and control valve 153. It is therefore possible to deliver either condensate or makeupwater to either jet 59' or the spray 56', although it will be.understood that under ordinary circumstances spray 56' will be supplied with recirculated water from the pump 145, while the jet 59 is supplied with makeup water through the pipe 151.

The. evaporator 144 includes a jet 154 similar to jet 66 and disposed within the upper portion of the evaporator 144 :which discharges into a second jet 156 arranged in series with the jet 154. A pipe 157 having a branch 158 supplies bled steam from an appropriate stage of the turbine to the jet 154 and through the branch 158 to the jet 156. Alternatively, a suitable three-way valve 160 may be mounted in branch 158 to shut off the supply of steam from pipe 157 and permit the introduction of higher pressuresteam through pipe 165 which is connected to a higher stage of the turbine 10. The jet 156 discharges through a check valve 170 into pipe 173, which communicates with a deaerator 159 within which is disposed a spray pipe 161 connected to pipe 141 for spraying condensate into the deaerator. The spray of condensate emerging from the spray pipe 161 condenses the vapors discharged into the deaerator by jet 156, thereby permitting thedeaerator to function as a condenser and simultaneously heating the condensate, and deaerating the water which is recycled to the boilers 13 through a pump 161 anda pipe 162'.

To eliminate non-condensible gases, a condenser 163 is mounted abovethe deaerator 159 and communicates therewith, its function being to condense Water vapor passingito. the condenser 163 and return the water to the deaerator 159. Non-condensible gasesare exhausted 8 front the. condenser 163- bya suitable pump 164 such as a steam jet: air pump, a water operated jet pum'p' or-the like, or vented directly to atmosphere. The-pipe 17311215- a control valve 174 and a branch: line 176 havinga valve" 177 from which steam for process or other use may be extracted.

The cycleand apparatus shown in Fig. 4 permit's'greater heatingand compression of the low temperature vapors, primarily by using steam jets operating in series. since this is frequently desirable, it shouldbe appreciated that jets arranged in series may be used as required, andmay be substituted for jets 16', 66, 117,. and 123 installations where appreciable fluctuations in load may be expected, it is often desirable to provide severaljets, such as the jet 66 in the same sub-atmospheric evaporator,

said jets operating in parallel in the same manner as a single jet, but with increased capacity. The additional jets may be brought into operation as desired, as for example during periods when the level of condensatein the hot well is high, or when additional makeup water is to be provided.

It should not be understood. from the foregoing that only the specific type of vacuum evaporators hereinbefor'e'" illustrated are-essential to the operation ofmy heat'cycle';

since various other arrangements are both permissible and eflicient. For example, as illustrated in Fig. 6, the'evap orator may comprise a shell 166 having a jet 66' mounted therein above banks of tubes 46". Water may be circulated through the tubes 46 from a header 47 to a" An inlet water box 49 and back to a return header 51'. pipe having a float control valve 167 receives condensate, makeup water, or a mixture thereof for intro= duction into the evaporator. This liquid is pumped from a well 168 in the bottom of the evaporator through a pump 169 to a spray 171 disposed within the evaporator above the tubes 46", thus providing positive means for" recirculating the water in the evaporator at any desired rate. If desired, an air vent 172 may be formed in the upper portion of the evaporator shell 166 and connected to a suitable exhauster or pump to remove air from the system.

It will be noted that in each of the foregoing instances,

heat from the steam exhausted into the main condenser has been processed in such manner as to form a vapor having a temperature and pressure sufficient to perform useful work as distinguished from simply condensing the vapor carrying the latent heat and dissipating the heat" water evaporator is not required and means are provided for evaporating condensate in instances where no makeup water is to be added. The proper application of control valves makes the operation of my cycle largely automatic in nature and permits its practical application to large installations with a minimum of supervision. The increase in actual economy effected by my cycle and apparatus is on the order of one percent as compared with other modern turbo-generator installations which do not incorporate all of the features in my invention.

The various arrangements herein described are to be considered as merely illustrating specific applications of 1 my invention and should not be interpreted as limitations; since obviously many additions and modifications may be made in a mannerobvious to those skilled in the art without departure from the herein disclosed principals.

I do not, therefore limit myself to the precise details herein disclosed, except insofar as defined in the appended claims.

I claim: 1. Heat cycle apparatus comprisinga multi-sta'ge tur- In large bine to-which relatively high pressure steam is supplied; a condenser having means for circulating a cooling medium in heat exchange relationship with the steam exhausted from said turbine for condensing the same, said circulating means being divided into a plurality of sections; a first and second vacuum evaporator in each of which water supplied thereto is evaporated to produce a cooling effect; a deaerator for receiving condensate and vapor; and ejectors disposed in the upper portion of each vacuum evaporator; a low pressure bleed steam line leading from said turbine to the ejector of said first vacuum evaporator and a vapor line leading therefrom to said deaerator; a condensate line leading from said condenser to said deaerator and having a branch leading to said first vacuum evaporator; a medium and a high pressure stage heater; a condensate line leading from said deaerator through said stage heaters in succession; a medium pressure bleed steam line leading from said turbine to the ejector of said second vacuum evaporator and a vapor line leading therefrom to said medium pressure stage heater; a makeup water line leading to said first and second vacuum evaporators; a cooling medium cycling line leading from one of said condenser sections and having branches leading in parallel relation to said vacuum evaporators and then back to said condenser section, said cycling line branches being adapted to pass said cooling medium in heat exchange relationship with the evaporating liquid in said vacuum evaporators; a high pressure bleed steam line leading from said turbine to said high pressure stage heater; a line leading from said high pressure stage heater to said medium stage heater for carrying condensed liquid adapted to flash into steam in said medium pressure stage heater; and a line leading from said medium pressure stage heater to said deaerator for carrying condensed liquidthereto.

2. Heat cycle apparatus comprising a multi-stage turbine to which high pressure steam is supplied; a condenser provided with means for circulating a cooling medium in heat exchange relationship with the steam exhausted from said turbine for condensing the same, said circulating means being divided into at least two sections; a vacuum evaporator provided with tubes for passing a medium in heat exchange relationship with a liquid evaporating therein; means connecting one of said condenser sections with said tubes for continuously cycling a cooling medium through said condenser section and through said tubes; an ejector in the upper portion of said vacuum evaporator for maintaining a relatively low absolute pressure therein; a bleed steam line leading from said turbine to said ejector; a spray pipe extending into said vacuum evaporator for spraying water into the space within said vacuum evaporator; a spray water recirculation line including a pump for recirculating spray water from the lower portion of said vacuum evaporator through the spray pipe; a feed water makeup line connected with said spray pipe; at condensate line leading from the lower portion of said condenser and having a check-valved branch connected with said cooling medium cycling line and another branch connected with said spray water recirculation line, a makeup water line connected with said spray pipe; a combined condenser and deaerator having an air-removal condensing trap at the top thereof; a spray means within said condensing deaerator connected with said condensate line; and a line leading from said ejector to said condensing deaerator for leading the mixture of bleed steam and vapor from said ejector to said condensing deaerator.

3. A vacuum evaporator comprising a shell, means connected with the upper portion of said shell for maintaining relatively low absolute pressure therein, means for introducing into said shell a jet of liquid to be evaporated, means for passing a liquid to be cooled in heat exchange relationship with said liquid to be evaporated, and a wheel rotatably mounted within said shell and positioned to be driven by said jet of liquid for moving liquid from the lower pontion of said shell to a point above said heat exchange means to cause such liquid-to flow downwardly over said heat exchange means.

4. In a system including a steam cycle wherein water is passed to a boiler for heating to produce steam, such steam is passed through a turbine, the exhaust steam from said turbine passes into a surface condenser, and the con densate is returned to the boiler for recycling, the improvement which comprises establishing a cooling cycle by which heat is transferred from a cooling medium circulating through a portion only of said condenser by evaporation of a liquid, including condensate from said condenser in heat exchange relationship with said cooling medium; and maintaining a relatively low absolute pressure in the space in which said liquid evaporates by bleeding steam from said turbine and passing such steam through an ejection passage.

5. In a system including a steam cycle, the improvement defined in claim 4, wherein said evaponatting liquid also includes makeup water.

6. In apparatus for the generation of electrical energy or the like, including a boiler, a prime mover supplied with steam from said boiler, a condenser for condensing the steam discharged from said prime mover, and means for extracting steam prior to the discharge from said prime mover, the improvement which comprises a condenser having a plurality of heat exchange passages for the independent circulation of a heat-exchange medium from at least two different sources; an evaporator having means therein for heat exchange between a first heat-exchange medium circwlating therethrough and an evaporating liquid; means for passing said first heat-exchange medium through one of said condenser sections, then through said evaporator, and then back to said condenser section; means for circulating a second heat-exchange medium through the other section of said condenser; means for supplying a liquid to be evaporated to the evaponating space in said evaporator; an ejector for producing a relatively low absolute pressure in said evaporating space; and means for supplying said extnacted steam to said ejector.

7. In apparatus as defined in claim 6, including a closed feed Water heater for the condensate from said condenser; and means for supplying the mixture of extracted steam and vapors removed from said evaporating space to said closed feed water heater for heating said condensate.

8. In heat cycle systems, including a primary cycle wherein a vaporizab'le and condensable fluid, while in the gaseous state, is passed through a prime mover adapted to produce mechanical energy, said gaseous fluid after passage through said prime mover being condensed byheat exchange with a cooling medium, the improvement which comprises passing at least a portion of said cooling medium in heat exchange relationship with an evaporating liquid to remove heat from said portion; extracting gaseous fluid from said primary cycle and supplying it to tan ejector for converting the heat energy thereof into kinetic energy to produce a suction effect and employing said effect to maintain a relatively low absolute pressure upon said evaporating liquid; mixing said extraoted gaseous fluid in the ejector with the vapors resulting from such liquid evaporation; and utilizing at least av portion of said mixture of extracted fluid and vapor as relatively high heat value vapor, externally of said primary cycle, 'the remainder of said mixture being returned to said primary cycle as a regenerative heating medium.

9. In heat cycle systems, the improvement defined in claim 8, including utilizing the entire mixture of extracted fluid and vapor as relatively high heat value vapor externally of said primary cycle.

10. In heat cycle systems, including a primary cycle wherein a vaporizable and cond'ensable fluid, while in the gaseous state, is passed through a prime mover adapted to produce mechanical energy, and is condensed after passage through said prime mover, and a cooling cycle for condensing said gaseous fluid after passage through said prime mover, the improvement which comprises extracting gaseous fluid from said primary cycle; maintaining a relatively low absolute pressure in a predetermined space by an ejection effect produced by passing said extracted gaseous fluid through an ejector; evaporating a liquid in said space to obtain a cooling effect; condensi'nga't least a portion of said primary cycle gaseous fluid, after passage through said prime mover, by at least indirect heat-exchange with said evaporating liquid; mixing sad extracted fluid in the ejector with gaseous fluid removed from said evaporating space; maintaining the temperature of the extracted fluid such that the removed mixture is primarily a gaseous fluid having available latent heat of evaporation; and passing said extracted fluid to a point of use of relatively low temperature gaseous fluid externally of said primary cycle.

11. In apparatus as defined in claim 10, including rn'e'a'n's for supplying the mixture of extracted steam and vapors removed from said evaporating space, to a point of use externally of said apparatus.

12. In a heart cycle including a primary cycle wherein steam is passed through a prime mover to produce mechanical energy and subsequently condensed by heat exchange with cooling medium, the improvement which comprises passing makeup water through a heat exchanger in heat transfer relationship with the steam exhausted from the prime mover for transferring at least a portion of the heat in the exhaust steam to the makeup water, producing vapor from the heated makeup water under sub-atmospheric pressure, bleeding steam from the prime mover and supplying it to an ejector for maintaining the sub-atmospheric pressure and 'for increasing the temperature and pressure of the vapor While maintaining said vapor in vapor form, and utilizing said compressed and heated vapor and subsequently returning the vapor to the primary cycle after condensation.

13. A steam cycle system comprising a boiler and a turbine and a surface condenser connected in a closed fluid circuit, conduit means for circulating a cooling medium through said condenser in heat exchange relationship with steam therein, means for passing a liquid over a portion of the surface of said first-mentioned means in heat exchange relationship with the cooling medium circulating therethrough, means including an ejector for maintaining a relatively low absolute pressure about said portion of the surface of said first means to facilitate r evaporation of said liquid and to Withdraw the resulting vapors, and means for bleeding steam from said turbine to actuate said ejector.

14. A steam cycle system as set forth in claim 13 and including means for connecting the discharge of said ejector with said closed circuit for returning the bled steam and evaporated liquid to said circuit.

15. In apparatus for generating electric energy and the like including a boiler, a prime mover supplied with steam from said boiler, a condenser for condensing the steam discharge from the prime mover, and means for extracting steam prior to the discharge from said prime mover to the condenser, the improvement which comprises a first heat exchanger disposed in the condenser, means for circulating cooling Water through said heat exchanger, an evaporator having a second heat exchanger formed therein for receiving heated cooling water from said first heat exchanger in the condenser and discharging said water after passage through the second heat exchanger to the first heat exchanger for further heating, means for supplying a liquid to be evaporated to the evaporator, an ejector discharging vapor from the evaporator, an'd means for supplying steam to the ejector at a temperature and pressure sufficient to maintain an absolute pressure in the evaporator below the absolute pressure maintained within the condenser.

16. In a steam driven prime-mover system, means including a spray connected to introduce cooling Waterinto a portion of said system in heat exchange relationship with steam exhausted from the prime mover for utilizing a portion of the latent heat of the steam to vaporize the introduced cooling water, means including an evacuiator connected to receive bled steam from the prime mover for maintaining a sub-atmospheric pressure in said portion of said system and for withdrawing the vaporized cooling Water therefrom and for producing a dry vapor mixture, and means for utilizing the heat of said mixture in said system.

17. In a steam driven prime mover system including a boiler and a surface condenser connected in a closed circuit wtih the prime mover, means including a steam ejector for removing from said circuit a portion of the latent heat of the steam exhausted by said prime mover, means for bleeding steam from said prime mover to actuate said ejector, and means in said system for utilizing the heat removed by said ejector means.

References Cited in the file of this patent UNITED STATES PATENTS 789,159 Lillie May 9, 1905 836,661 Sturnpf May 5, 1908 1,031,199 Rigney July 2, 1912 1,361,834 De Baufre Dec. 14, 1920 1,390,676 De Baufre Sept. 13, 1921 1,689,336 Grifiin Oct. 30, 1928 1,778,745 Ayers Oct. 21, 1930 1,970,296 Fleisher Aug. 14, 1934 1,993,288 Smith et a1. Mar. 5, 1935 2,278,085 Ostermann Mar. 31, 1942 2,441,361 Kirgan May 11, 1948 

